Text-fig. 64. “Buglossa” [Ortus Sanitatis, Mainz, 1491].
Pliny was not, strictly speaking, a medical botanist, but at the same time he may be mentioned in this connection, since his interest in plants was essentially utilitarian. Like Theophrastus, he begins his account of plants with the trees, but his reason for so doing is profoundly different from that of the Greek writer, and illustrates the divergence between what we may call the anthropocentric and the scientific outlook upon the plant world. Theophrastus placed trees at the head of the vegetable kingdom, because he considered their organisation the highest, and most completely expressive of plant nature; Pliny, on the other hand, began with trees because of their great value and importance to man. As an example of his ideas of arrangement, we may mention that he places the Myrtle and Laurel side by side, because the Laurel takes a corresponding place in triumphs to that accorded to the Myrtle in ovations!
Turning to the herbals themselves, we find that the earliest show no trace of a natural grouping, the plants being, as a rule, arranged alphabetically. This is the case, for instance, in the Latin and German Herbarius, the Ortus Sanitatis and their derivatives, and even in the herbals of Brunfels and of Fuchs in the sixteenth century. In Bock’s herbal, on the other hand, the plants are grouped as herbs, shrubs and trees, according to the classical scheme. The author evidently made some effort, within these classes, to arrange them according to their relationships. In the preface to the third edition he writes—“I have placed together, yet kept distinct, all plants which are related and connected, or otherwise resemble one another and are compared, and have given up the former old rule or arrangement according to the A.B.C. which is seen in the old herbals. For the arrangement of plants by the A.B.C. occasions much disparity and error.”
Although the larger classificatory divisions, as now understood, were not recognised by these early workers, they had at least a dim understanding of the distinction between genera and species. This dates back to Theophrastus, who showed, by grouping together different species of oaks, figs, etc., that he had some conception of a genus. We owe to Konrad Gesner the first formulation of the idea that genera should be denoted by substantive names. He was probably the earliest botanist who clearly expounded the distinction between a genus and a species. In one of his letters he writes—“And we may hold this for certain, that there are scarcely any plants that constitute a genus which may not be divided into two or more species. The ancients describe one species of Gentian; I know of ten or more.”
Very little of Gesner’s botanical work was ever published, and it was left to Fabio Colonna to put before the botanical world the true nature of genera. He held most enlightened views on the subject, and, in 1616, clearly stated in his ‘Ekphrasis’ that genera should not be based on similarities of leaf form, since the affinities of plants are indicated not by the leaf, but by the characters of the flower, the receptacle, and, especially, the seed[29]. He brought forward instances to show that previous authors had sometimes placed a plant in the wrong genus, because they only attended to the leaves and ignored the structure of the flower.
Text-fig. 65. “Nenufar” = Waterlily [Arnaldus de Villa Nova, Tractatus de virtutibus herbarum, 1499].
In the writings of Gaspard Bauhin, at the end of the sixteenth and the beginning of the seventeenth century, the binary system of nomenclature is used with a high degree of consistency, each species bearing a generic and specific name, though sometimes a third, or even a fourth, descriptive word is added. These extra words are not,